涛涛GWD31中的GWD3-2~GWD3-33Thanx~~

我翻了讨论贴，题号和我做的gwd为啥对不上呢。。

下面这2题怎解？偶对概率的题目没有什么概念。。。高中偶也没有学。。答案B thanx~

Q2:

On Saturday morning, Malachi will begin a camping vacation and he will return home at the end of the first day on which it rains.  If on the first three days of the vacation the probability of rain on each day is 0.2, what is the probability that Malachi will return home at the end of the day on the following Monday?

A.     0.008

B.     0.128

C.     0.488

D.     0.512

E.      0.640

还有一道排列组合的题目。。。答案A

Q33:

A photographer
   will arrange 6 people of 6 different heights for photograph by placing them in two rows of three so that each person in the first row is standing in front of someone in the second row.  The heights of the people within each row must increase from left to right, and each person in the second row must be taller than the person standing in front of him or her.  How many such arrangements of the 6 people are possible?

A.     5

B.     6

C.     9

D.     24

36

做整套的数学题之前可以复习下系统的基础知识。

可以参考QYQ GMAT数学难题精解，下面链接2楼有下载:

http://forum.chasedream.com/dispbbs.asp?boardID=22&ID=143895&page=1

另外MM这个题是涛涛版GWD31套中的吧？如是，请注明

再就是如果问多道题，请将题号逐一在标题中标出，谢谢配合！

周一回来，说明周六没下雨，周日没下雨，周一下雨了。

每天下雨的概率是0.2，不下是0.8

所以周一回来的概率就是周六不下雨的概率×周日不下雨的概率×周一下雨的概率＝0.8*0.8*0.2＝0.128

 不好意思，忘记说是GWD31了，打字后面一个题号打漏了

有没有可以用排列组合计算的方法呢？偶怕万一遇到个多的，咋办a?

同样求助谢谢